Fifteen million Americans suffer from asthma, and the burden of morbidity appears to be rising. Asthma is also a major cause of health disparities among minority and low socio-economic groups. Yet the increasing prevalence and marked disparities in asthma remain largely unexplained by known risk factors, suggesting the potential role of community-level factors. The aim of this application is to enable the candidate to undertake training and mentored research to address the question: what is the role of community and neighborhood-level processes in explaining the occurrence and distribution of asthma? The candidate has expertise in multilevel statistical modeling with substantive interest in the social determinants of health. Over the next five years, the candidate will gain training in: (1) asthma epidemiology and pathophysiology, (2) the theory and measurement of neighborhood-level processes, and (3) causal inference within a multilevel framework. Applying a multilevel approach that explicitly recognizes the embedding of asthma within its biologic, socioeconomic, environmental, and community contexts, the candidate will conduct mentored research to examine the causes of asthma disparities at different stages in the life-course. The proposed analysis will be carried out within three ongoing studies (Asthma Coalition on Community, Environment, and Social Stress; Boston Area Community Health Study; and Project on Human Development in Chicago Neighborhoods) in two American cities (Boston and Chicago). The research will examine the potential roles of neighborhood attributes such as structural disadvantage, collective psychosocial characteristics and physical environmental conditions in explaining the known disparities in the prevalence of asthma. The proposed award will be used to develop an integrative and transdisciplinary approach to these issues, drawing on the rich resources available within Harvard University, including access to community-based study populations as well as to expertise from multiple fields.